Electric steel furnace or the like



May 14, 1940. w. LINDER ELECTRIC STEEL FURNACE OR THE LIKE Filed May 11,1938- 2 Sheets-Sheet 1 Jr; ve nfor:

May 14, 1940. w. LINDER ELECTRIC STEEL FURNACE OR THE LIKE Filed May 11,1938 2 Sheets-Sheet 2 Jnvenfo/z- Patented May 14, 1940 PATENT OFFICEELECTRIC STEEL FURNACE OR THE LIKE Willy Linder, Essen, Germany,assignor, by mesne assignments, to Koppers Company, Pittsburgh, Pa., acorporation of Delaware Application May 11, 1938, Serial No. 207,295 InGermany May 12, 1937 6 Claims.

The present invention relates to electric steel furnaces and otherfurnaces with a roof of refractory material supported. by a frameindependently of the anchorage of the side walls of the furnace, andmore particularly to those electric steel furnaces or the like in whicha removable coverconsisting of refractory material is provided upon thefurnace, said cover being constructed like an arch and arranged within aring- .10 shaped frame.

The arched roof of the electric steel furnaces known hitherto issupported by a rigid frame. The refractory bricks of the arched roof,however, expand to quite a considerable extent when the temperature ofthe furnace is raised to the very high operating temperature necessaryfor the production of steel or other materials. Since the frame of theroof as provided in the known steel furnaces cannot expand or give wayin radial direction, the heat expansion of the roof bricks will forcethe material inwardly and this will cause a raising-upwards of the archtowards the centre thereof. If the refractory material of the furnaceroof expands in this way, then the roof bricks no longer touch oneanother along their whole side faces, but only with their inner edges orwith small zones adjacent thereto. Consequently, certain points of theindividual brick are highly stressed and the inner edges of the 80bricks tend to crack or spell-off. The life of the arched roof of theknown electric steel furnaces is therefore comparatively short.

The main object of my present invention is to provide such improvementsin electric steel furnaces Or other furnaces fitted with an arched roofthat is anchored independently of the furnace side walls, which willallow a heat expansion of the refractory material of the furnace roofwithout exerting any dangerous additional 40 stresses upon the roofbricks.

My present invention principally consists in holding the refractorybrickwork of the roof of electric steel furnaces or the like together atthe circumferenceof the roof by elastic means, which 5 are fixed to arigid ring-shaped supporting frame,

and against the pressure of springs arranged between the rigid frame andthe said elastic supporting elements.

Another important feature of my invention in- 59 eludes the novelarrangement of the bricks in the bricklining of the roof of furnaces,and final ly my invention also comprehends the provision of means whichenable the exact adjustment of the posltion of the elastic supportingelements relatively to the rigid supporting frame, and

limit the movement of the said supporting elements.

With the above and other objects and features of my present invention inview, I will now describe a preferred embodiment of my invention 6 onthe lines of the accompanying drawings, in which Figure 1 shows avertical section through the roof of the electric steel furnace builtaccording to my present invention said view being taken 10 in part onthe line A-A and in part on the line' BB.

Figure 2 is a side elevational view of the lateral framing of the roofon an enlarged scale.

Figure 3 is a view from below the roof accord- 1 ing to Figure 1.

The reaction or melting chamber of an electric steel furnace, onlypartly shown on the drawings, has been marked in the figure with l thefurnace comprises the refractory brickwork 2 and the steel shell 3,enclosing the brickwork. The furnace chamber is closed at the top bymeans of the removable arch 4 which is traversed by the electrodes 5.The arched roof is covered on the outside by an insulating layer 6.

The arch is held by a tension frame consisting of a multitude ofadjoining segment-like brick clamp supports 1 which are conformed to acircle in the design of the arch illustrated on the drawings.

The brick clamp supports 1 are suspended in a closed ring-shaped frame Iby the means of the carrying levers I3 and fulcrum levers 9. Thesuspension, in the mode exemplifying this kind of construction, iseffected in such a manner that $5 thefulcrum levers 9 engage in groovessuitably arranged on the circumference of the frame 8 by means of bushesIt so that the clamp supports I may move about these points as pivots.The supporting frame I is further fitted with bearings H which aretraversed, for a greater play, by the tension bolts II, which tie thecarrying levers l3 of the supports 1 with the carrying frame 8, thebolts, at a certain distance behind the bearing, carrying thepressure-springs H, the tension of which is adjusted by screw-nuts II.Figure 1 of the drawings indicates the arch in cold condition. In thisstate, the carrying lever 13 fits directly against the supporting framebearing II. In working condition, the pressure spring I4 is compressedby the degree of expansion so that the brick clamp supports I, togetherwith the carrying levers l3 and fulcrum levers 9 assume the positionindicated at A in dash and dot lines on the drawings, when the fulcrum-cold layers of the levers l3 together with the screw bolts l2 adjustthemselves in corresponding to the movement about the turning point Ill.

Each brick clamp support I is fitted with at least one fulcrum lever 9suspended from the fulcrum point It, and furthermore with two or severalpressure-members l2, [4 supported by the supporting frame 8. In order toavoid a too considerable displacement of the roof bricks, and thus aloosening of same, in case of failure of the pressure screws l4, orrelaxing of the tension, the fulcrum levers 9 and supporting frames 8are also connected together by set screws IS, the nuts I! of which areadjusted in such a manner that they form a limitation for the greatestpossible expansion of the arch in which the bricks still fit tightlyagainst one another.

The supports 1 are fitted below with a flange 18 to which is affixed avertical sheet-iron sealing frame 19 lying in a sand seal 20 so that agas-tight closure for the furnace is ensured. In order to avoid acooling-down of the interior of the furnace at the bearing face of theclamp supports 1, a refractory packing mass 2| is provided between thebrickwork 2 of the substructure and the arch 4 of the electric steelfurnace.

The arch 4 is suspended from a supporting frame 23, through thesuspension frame 8, by means of eye-hooks 22 aflixed to same. Theeyehooks 22 are for this purpose connected with pulling devices 24 whichrun over the rollers 25 on the supporting frame 23 and which areoperated by a driving shaft, not shown on the drawmgs.

The process of pouring-out the melting bath is preferably carried out insuch manner that the arched cover is removed from the furnace, thefurnace is moved to the side and then tilted. After the discharge, thefurnace is suitably topcharged during the run, the furnace is driven-inagain and the cover placed on. In this way, an appreciable cooling downof the furnace as well as of the arch is avoided.

It must be mentioned that levers or the like capable of being put underpressure may be used instead of the pressure springs l4.

The efficiency of the furnace roof designed in accordance with thebefore mentioned description will also be considerably improved if thebricks of the arched cover-in the outer layers adjoining the supports 1are not laid in a continuous bond, but if they form segments ofbrickwork laid in a bond which correspond to the length of theindividual supports 1, while the roof bricklining towardsthe centre iscarried out as usual in a continuous bond.

This is of advantage since the movable supports can be pressedJoackagain corresponding to the heat expansion of the bricks, withoutnecessitating provision of means for supplying an additional pressurefor overcoming the friction of the roof bricks, due to theinterconnection of the roof bricks in the outer arched cover. In case oflarge covers, the friction of the roof bricks in the outer layers, ifthe arched-roof is constructed in a continuous bond, may under certainconditions be to such a considerable degree that the movable arrangementof the roof supports is thus rendered ineffective.

Figure 3 of the drawings clearly shows the new arrangement of theroofbrickwork. The mode of carrying out the invention according to Figure 3corresponds to the arrangement of Figures 1 and 2 as regards the roofconstruction in general. The outer layers 32 of the roof brick-liningadjoining the segment-like supports 3| are laid in a bond in segments asmay be seen from Figure 2. The various groups or segments thus formedare separated from one another by continuous joints 33. The internalsections of the roof arch 34 are, however, laid in a continuous bond.

The insulating layer placed above the roof, is likewise suitably carriedout in a continuous bond. This layer generally consists of light brickswhich are able to follow easily the movement of the roof supports.Should it happen, that the joints 33 gape during the operation, asufficient seal is easily obtained by the insulating layer, situatedabove the roof, as shown in Figure 1.

Various changes may be made in the details of the construction of theforegoing specification, without departing from the invention and theadvantages thereof, since the invention is not limited in all itsaspects to the mode of carrying it out as described and shown, but maybe variously embodied within the scope of the following claims.

I claim:

1. Metallurgical furnace or the like with the arched roof of the furnacesupported independently of the side walls of the furnace, comprising arigid frame mounted so as to be lowered and lifted into and out ofoperative relationship. with the furnace, a multitude of segment-likesupports carried by said frame, said segment-like supports surroundingthe arched furnace roof consisting of refractory bricks and clampinglysupporting the bricks in contiguous relationship with each other, saidsegment-like supports being arranged moveably on said rigid frame insuch a manner, that the said supports may move in a generally radialdirection and means for adjusting the said segment-like supports, therigid frame being spaced from the arch roof so as to be entirely clearof the same, the bricks of the roof being free of support by suspensorymeans between its margins and being otherwise unsupported other than bythe segment-like supports that surround the arched roof, and the spacedrigid frame and segment like supports for clamping the bricks alsoconstituting the sole load carrying and supporting means for the archedroof and its bricks.

2. Metallurgical furnace or the like with the arched roof of the furnacesupported independently of the side walls of the furnace, comprising arigid frame mounted so as to be lowered and lifted into and out ofoperative relationship with the furnace, a multitude of segment-likesupports carried by said frame, said segment-like supports surroundingthe arched furnace roof consisting of refractory bricks and clampinglysupporting the bricks in contiguous relationship with each other, saidsegment-like supports being arranged moveably on said rigid frame insuch a manner, that the said supports may move in radial direction,spring means arranged between said rigid frame and said segment-likesupports so as to draw the latter to the former in such manner that thesaid segment-like supports are forced towards the center of the archedroof, the rigid frame being spaced from the arch roof so as to beentirely clear of the same, the bricks of the roof being free of supportby suspensory means between its margins and being otherwise unsupportedother than by the segment-like supports that surround the arched roof,and the spaced rigid frame and segment-like supports for clamping thebricks also constituting the sole load carrying and supporting means forthe arched roof and its bricks.

3. Metallurgical furnace or the like with the arched roof of the furnacesupported independently of the side walls of the furnace, comprising arigid frame mounted so as to be lowered and lifted into and out ofoperative relationship with the furnace, a multitude of segment-likesupports carried by said frame, said segment-like supports surroundingthe arched furnace roof consisting of refractory bricks and clampinglysupporting the bricks in contiguous relationship with each other, eachof said segment-like supports being connected with the frame by a. leverfulcrumed on said rigid frame in such a manner that the said supportsmay move about the fulcrum in a generally radial direction, and meansfor adjusting said segment-like supports, the rigid frame being spacedfrom the. arch roof so as to be entirely clear of the same, the bricksof the roof being free of support by suspensory means between itsmargins and being otherwise unsupported other than by the segment-likesup-. ports that surround the arched roof, and the spaced frame andsegment-like supports for clamping the bricks also constituting the soleload carrying and supporting means for the arched roof and its bricks.

4. Metallurgical furnace or the like with the arched roof at the furnacesupported independently of the side walls of the furnace,comprisingarlgidframe molmtedsoastobelowered and lifted out of operativerelationship with the furnace, a multitude of segment-like supportscarried by the said frame, said segment-like surrounding the archedfurnace roof of refractory bricks and clampingly the bricks incontiguous relationship with each other, each of said segment-likesupports being connected with the frame by a leverfulcrmnedonsaidrigidframeinsuchamanner that the said supports may moveabout the fulcrumin agenenllyradialdirectiomandmeans fa: saidsegment-like supports, the

bearings for said levers being arranged on the outer surface of saidrigid frame, the rigid frame being spaced from the arch roof so as to beentirely clear of the same, thebricks of the roof being free of supportby suspensory means between its margins and being otherwise unsupportedother than by the segment-like supports that surround the arched roof,and the spaced rigid frame and segment-like supports for clamping thebricks also constituting the sole load carrying and supporting means forthe arched roof and its bricks.

5. In a furnace roof provided with means as set forth in claim 1, theroof bricks in the outer zones of the roof adjacent to said segment-likesupports being in individual segments independent from one another andcorresponding to said supports, the central part of said furnace mebeing arranged in a bond.

6. Electric steel furnace or the like with thearched roof of the furnacesupported independently of the anchorage of the side walls of thefurnace, comprising a ring-shaped rigid frame mounted so as to belowered and lifted into and out of operative relationship with thefurnace, a multitude of segment-likesupports carried by said frame, saidroof consisting of refractory bricks and said segment-like supportssurrounding the arched furnace roof and clampingly supporting the bricksin contiguous relationship with each 'other, said segment-like supportsbeing arranged moveably on said ring-shaped rigid frame in such amanner, that the said supports may move in radial direction and meansfor adjusting the said segment-likesupports, the ring-shaped rigid framebeing spaced from the arch roof so as to be entirely clear of the same,the bricks of the roof being free of support by suspensory means betweenits margins and being otherwise unsupported other than by thesegment-like supports that surround the arched roof, and the spacedrigid frame and segment like Supports for clamping the bricks alsoconstituting the sole load carrying and supporting means for the archedroof and its bricks.

WILLY LINDER.

